1 ;;;; structures for the first intermediate representation in the
4 ;;;; This software is part of the SBCL system. See the README file for
7 ;;;; This software is derived from the CMU CL system, which was
8 ;;;; written at Carnegie Mellon University and released into the
9 ;;;; public domain. The software is in the public domain and is
10 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
11 ;;;; files for more information.
15 ;;; The front-end data structure (IR1) is composed of nodes and
16 ;;; continuations. The general idea is that continuations contain
17 ;;; top-down information and nodes contain bottom-up, derived
18 ;;; information. A continuation represents a place in the code, while
19 ;;; a node represents code that does something.
21 ;;; This representation is more of a flow-graph than an augmented
22 ;;; syntax tree. The evaluation order is explicitly represented in the
23 ;;; linkage by continuations, rather than being implicit in the nodes
24 ;;; which receive the the results of evaluation. This allows us to
25 ;;; decouple the flow of results from the flow of control. A
26 ;;; continuation represents both, but the continuation can represent
27 ;;; the case of a discarded result by having no DEST.
29 (def!struct (continuation
30 (:make-load-form-fun ignore-it)
31 (:constructor make-continuation (&optional dest)))
32 ;; An indication of the way that this continuation is currently used:
35 ;; A continuation for which all control-related slots have the
36 ;; default values. A continuation is unused during IR1 conversion
37 ;; until it is assigned a block, and may be also be temporarily
38 ;; unused during later manipulations of IR1. In a consistent
39 ;; state there should never be any mention of :UNUSED
40 ;; continuations. Next can have a non-null value if the next node
41 ;; has already been determined.
44 ;; A continuation that has been deleted from IR1. Any pointers into
45 ;; IR1 are cleared. There are two conditions under which a deleted
46 ;; continuation may appear in code:
47 ;; -- The CONT of the LAST node in a block may be a deleted
48 ;; continuation when the original receiver of the continuation's
49 ;; value was deleted. Note that DEST in a deleted continuation is
50 ;; null, so it is easy to know not to attempt delivering any
51 ;; values to the continuation.
52 ;; -- Unreachable code that hasn't been deleted yet may receive
53 ;; deleted continuations. All such code will be in blocks that
54 ;; have DELETE-P set. All unreachable code is deleted by control
55 ;; optimization, so the backend doesn't have to worry about this.
58 ;; The continuation that is the START of BLOCK. This is the only kind
59 ;; of continuation that can have more than one use. The BLOCK's
60 ;; START-USES is a list of all the uses.
62 ;; :DELETED-BLOCK-START
63 ;; Like :BLOCK-START, but BLOCK has been deleted. A block
64 ;; starting continuation is made into a deleted block start when
65 ;; the block is deleted, but the continuation still may have
66 ;; value semantics. Since there isn't any code left, next is
70 ;; A continuation that is the CONT of some node in BLOCK.
71 (kind :unused :type (member :unused :deleted :inside-block :block-start
72 :deleted-block-start))
73 ;; The node which receives this value, if any. In a deleted continuation,
74 ;; this is null even though the node that receives this continuation may not
76 (dest nil :type (or node null))
77 ;; If this is a NODE, then it is the node which is to be evaluated
78 ;; next. This is always null in :DELETED and :UNUSED continuations,
79 ;; and will be null in a :INSIDE-BLOCK continuation when this is the
81 (next nil :type (or node null))
82 ;; an assertion on the type of this continuation's value
83 (asserted-type *wild-type* :type ctype)
84 ;; cached type of this continuation's value. If NIL, then this must
85 ;; be recomputed: see CONTINUATION-DERIVED-TYPE.
86 (%derived-type nil :type (or ctype null))
87 ;; Node where this continuation is used, if unique. This is always
88 ;; null in :DELETED and :UNUSED continuations, and is never null in
89 ;; :INSIDE-BLOCK continuations. In a :BLOCK-START continuation, the
90 ;; Block's START-USES indicate whether NIL means no uses or more
92 (use nil :type (or node null))
93 ;; the basic block this continuation is in. This is null only in
94 ;; :DELETED and :UNUSED continuations. Note that blocks that are
95 ;; unreachable but still in the DFO may receive deleted
96 ;; continuations, so it isn't o.k. to assume that any continuation
97 ;; that you pick up out of its DEST node has a BLOCK.
98 (block nil :type (or cblock null))
99 ;; set to true when something about this continuation's value has
100 ;; changed. See REOPTIMIZE-CONTINUATION. This provides a way for IR1
101 ;; optimize to determine which operands to a node have changed. If
102 ;; the optimizer for this node type doesn't care, it can elect not
103 ;; to clear this flag.
104 (reoptimize t :type boolean)
105 ;; an indication of what we have proven about how this contination's
106 ;; type assertion is satisfied:
109 ;; No type check is necessary (proven type is a subtype of the assertion.)
112 ;; A type check is needed.
115 ;; Don't do a type check, but believe (intersect) the assertion.
116 ;; A T check can be changed to :DELETED if we somehow prove the
117 ;; check is unnecessary, or if we eliminate it through a policy
121 ;; Type check generation sets the slot to this if a check is
122 ;; called for, but it believes it has proven that the check won't
123 ;; be done for policy reasons or because a safe implementation
124 ;; will be used. In the latter case, LTN must ensure that a safe
125 ;; implementation *is* used.
128 ;; There is a compile-time type error in some use of this
129 ;; continuation. A type check should still be generated, but be
132 ;; This is computed lazily by CONTINUATION-DERIVED-TYPE, so use
133 ;; CONTINUATION-TYPE-CHECK instead of the %'ed slot accessor.
134 (%type-check t :type (member t nil :deleted :no-check :error))
135 ;; something or other that the back end annotates this continuation with
137 ;; uses of this continuation in the lexical environment. They are
138 ;; recorded so that when one continuation is substituted for another
139 ;; the environment may be updated properly.
140 (lexenv-uses nil :type list))
142 (def!method print-object ((x continuation) stream)
143 (print-unreadable-object (x stream :type t :identity t)))
145 (defstruct (node (:constructor nil))
146 ;; the bottom-up derived type for this node. This does not take into
147 ;; consideration output type assertions on this node (actually on its CONT).
148 (derived-type *wild-type* :type ctype)
149 ;; True if this node needs to be optimized. This is set to true
150 ;; whenever something changes about the value of a continuation
151 ;; whose DEST is this node.
152 (reoptimize t :type boolean)
153 ;; the continuation which receives the value of this node. This also
154 ;; indicates what we do controlwise after evaluating this node. This
155 ;; may be null during IR1 conversion.
156 (cont nil :type (or continuation null))
157 ;; the continuation that this node is the next of. This is null
158 ;; during IR1 conversion when we haven't linked the node in yet or
159 ;; in nodes that have been deleted from the IR1 by UNLINK-NODE.
160 (prev nil :type (or continuation null))
161 ;; the lexical environment this node was converted in
162 (lexenv *lexenv* :type lexenv)
163 ;; a representation of the source code responsible for generating
166 ;; For a form introduced by compilation (does not appear in the
167 ;; original source), the path begins with a list of all the
168 ;; enclosing introduced forms. This list is from the inside out,
169 ;; with the form immediately responsible for this node at the head
172 ;; Following the introduced forms is a representation of the
173 ;; location of the enclosing original source form. This transition
174 ;; is indicated by the magic ORIGINAL-SOURCE-START marker. The first
175 ;; element of the orignal source is the "form number", which is the
176 ;; ordinal number of this form in a depth-first, left-to-right walk
177 ;; of the truly top-level form in which this appears.
179 ;; Following is a list of integers describing the path taken through
180 ;; the source to get to this point:
181 ;; (K L M ...) => (NTH K (NTH L (NTH M ...)))
183 ;; The last element in the list is the top-level form number, which
184 ;; is the ordinal number (in this call to the compiler) of the truly
185 ;; top-level form containing the orignal source.
186 (source-path *current-path* :type list)
187 ;; If this node is in a tail-recursive position, then this is set to
188 ;; T. At the end of IR1 (in environment analysis) this is computed
189 ;; for all nodes (after cleanup code has been emitted). Before then,
190 ;; a non-null value indicates that IR1 optimization has converted a
191 ;; tail local call to a direct transfer.
193 ;; If the back-end breaks tail-recursion for some reason, then it
194 ;; can null out this slot.
195 (tail-p nil :type boolean))
197 ;;; Flags that are used to indicate various things about a block, such
198 ;;; as what optimizations need to be done on it:
199 ;;; -- REOPTIMIZE is set when something interesting happens the uses of a
200 ;;; continuation whose Dest is in this block. This indicates that the
201 ;;; value-driven (forward) IR1 optimizations should be done on this block.
202 ;;; -- FLUSH-P is set when code in this block becomes potentially flushable,
203 ;;; usually due to a continuation's DEST becoming null.
204 ;;; -- TYPE-CHECK is true when the type check phase should be run on this
205 ;;; block. IR1 optimize can introduce new blocks after type check has
206 ;;; already run. We need to check these blocks, but there is no point in
207 ;;; checking blocks we have already checked.
208 ;;; -- DELETE-P is true when this block is used to indicate that this block
209 ;;; has been determined to be unreachable and should be deleted. IR1
210 ;;; phases should not attempt to examine or modify blocks with DELETE-P
211 ;;; set, since they may:
212 ;;; - be in the process of being deleted, or
213 ;;; - have no successors, or
214 ;;; - receive :DELETED continuations.
215 ;;; -- TYPE-ASSERTED, TEST-MODIFIED
216 ;;; These flags are used to indicate that something in this block
217 ;;; might be of interest to constraint propagation. TYPE-ASSERTED
218 ;;; is set when a continuation type assertion is strengthened.
219 ;;; TEST-MODIFIED is set whenever the test for the ending IF has
220 ;;; changed (may be true when there is no IF.)
221 (def-boolean-attribute block
222 reoptimize flush-p type-check delete-p type-asserted test-modified)
224 (macrolet ((frob (slot)
225 `(defmacro ,(symbolicate "BLOCK-" slot) (block)
226 `(block-attributep (block-flags ,block) ,',slot))))
232 (frob test-modified))
234 ;;; The CBLOCK structure represents a basic block. We include
235 ;;; SSET-ELEMENT so that we can have sets of blocks. Initially the
236 ;;; SSET-ELEMENT-NUMBER is null, DFO analysis numbers in reverse DFO.
237 ;;; During IR2 conversion, IR1 blocks are re-numbered in forward emit
238 ;;; order. This latter numbering also forms the basis of the block
239 ;;; numbering in the debug-info (though that is relative to the start
240 ;;; of the function.)
241 (defstruct (cblock (:include sset-element)
242 (:constructor make-block (start))
243 (:constructor make-block-key)
246 (:copier copy-block))
247 ;; a list of all the blocks that are predecessors/successors of this
248 ;; block. In well-formed IR1, most blocks will have one successor.
249 ;; The only exceptions are:
250 ;; 1. component head blocks (any number)
251 ;; 2. blocks ending in an IF (1 or 2)
252 ;; 3. blocks with DELETE-P set (zero)
253 (pred nil :type list)
254 (succ nil :type list)
255 ;; the continuation which heads this block (either a :BLOCK-START or
256 ;; :DELETED-BLOCK-START), or NIL when we haven't made the start
257 ;; continuation yet (and in the dummy component head and tail
259 (start nil :type (or continuation null))
260 ;; a list of all the nodes that have START as their CONT
261 (start-uses nil :type list)
262 ;; the last node in this block. This is NIL when we are in the
263 ;; process of building a block (and in the dummy component head and
265 (last nil :type (or node null))
266 ;; the forward and backward links in the depth-first ordering of the
267 ;; blocks. These slots are NIL at beginning/end.
268 (next nil :type (or null cblock))
269 (prev nil :type (or null cblock))
270 ;; This block's attributes: see above.
271 (flags (block-attributes reoptimize flush-p type-check type-asserted
274 ;; Some sets used by constraint propagation.
279 ;; the component this block is in, or NIL temporarily during IR1
280 ;; conversion and in deleted blocks
281 (component *current-component* :type (or component null))
282 ;; a flag used by various graph-walking code to determine whether
283 ;; this block has been processed already or what. We make this
284 ;; initially NIL so that FIND-INITIAL-DFO doesn't have to scan the
285 ;; entire initial component just to clear the flags.
287 ;; Some kind of info used by the back end.
289 ;; If true, then constraints that hold in this block and its
290 ;; successors by merit of being tested by its IF predecessor.
291 (test-constraint nil :type (or sset null)))
292 (def!method print-object ((cblock cblock) stream)
293 (print-unreadable-object (cblock stream :type t :identity t)
294 (format stream ":START c~D" (cont-num (block-start cblock)))))
296 ;;; The Block-Annotation structure is shared (via :INCLUDE) by
297 ;;; different block-info annotation structures so that code
298 ;;; (specifically control analysis) can be shared.
299 (defstruct (block-annotation (:constructor nil))
300 ;; The IR1 block that this block is in the INFO for.
301 (block (required-argument) :type cblock)
302 ;; the next and previous block in emission order (not DFO). This
303 ;; determines which block we drop though to, and also used to chain
304 ;; together overflow blocks that result from splitting of IR2 blocks
305 ;; in lifetime analysis.
306 (next nil :type (or block-annotation null))
307 (prev nil :type (or block-annotation null)))
309 ;;; The Component structure provides a handle on a connected piece of
310 ;;; the flow graph. Most of the passes in the compiler operate on
311 ;;; components rather than on the entire flow graph.
313 ;; The kind of component:
316 ;; An ordinary component, containing non-top-level code.
319 ;; A component containing only load-time code.
321 ;; :Complex-Top-Level
322 ;; A component containing both top-level and run-time code.
325 ;; The result of initial IR1 conversion, on which component
326 ;; analysis has not been done.
329 ;; Debris left over from component analysis.
330 (kind nil :type (member nil :top-level :complex-top-level :initial :deleted))
331 ;; The blocks that are the dummy head and tail of the DFO.
332 ;; Entry/exit points have these blocks as their
333 ;; predecessors/successors. Null temporarily. The start and return
334 ;; from each non-deleted function is linked to the component head
335 ;; and tail. Until environment analysis links NLX entry stubs to the
336 ;; component head, every successor of the head is a function start
337 ;; (i.e. begins with a Bind node.)
338 (head nil :type (or null cblock))
339 (tail nil :type (or null cblock))
340 ;; A list of the CLambda structures for all functions in this
341 ;; component. Optional-Dispatches are represented only by their XEP
342 ;; and other associated lambdas. This doesn't contain any deleted or
344 (lambdas () :type list)
345 ;; A list of Functional structures for functions that are newly
346 ;; converted, and haven't been local-call analyzed yet. Initially
347 ;; functions are not in the Lambdas list. LOCAL-CALL-ANALYZE moves
348 ;; them there (possibly as LETs, or implicitly as XEPs if an
349 ;; OPTIONAL-DISPATCH.) Between runs of LOCAL-CALL-ANALYZE there may
350 ;; be some debris of converted or even deleted functions in this
352 (new-functions () :type list)
353 ;; If true, then there is stuff in this component that could benefit
354 ;; from further IR1 optimization.
355 (reoptimize t :type boolean)
356 ;; If true, then the control flow in this component was messed up by
357 ;; IR1 optimizations. The DFO should be recomputed.
358 (reanalyze nil :type boolean)
359 ;; String that is some sort of name for the code in this component.
360 (name "<unknown>" :type simple-string)
361 ;; Some kind of info used by the back end.
363 ;; The Source-Info structure describing where this component was
365 (source-info *source-info* :type source-info)
366 ;; Count of the number of inline expansions we have done while
367 ;; compiling this component, to detect infinite or exponential
369 (inline-expansions 0 :type index)
370 ;; A hashtable from combination nodes to things describing how an
371 ;; optimization of the node failed. The value is an alist (Transform
372 ;; . Args), where Transform is the structure describing the
373 ;; transform that failed, and Args is either a list of format
374 ;; arguments for the note, or the FUNCTION-TYPE that would have
375 ;; enabled the transformation but failed to match.
376 (failed-optimizations (make-hash-table :test 'eq) :type hash-table)
377 ;; Similar to NEW-FUNCTIONS, but is used when a function has already
378 ;; been analyzed, but new references have been added by inline
379 ;; expansion. Unlike NEW-FUNCTIONS, this is not disjoint from
380 ;; COMPONENT-LAMBDAS.
381 (reanalyze-functions nil :type list))
382 (defprinter (component)
384 (reanalyze :test reanalyze))
386 ;;; The Cleanup structure represents some dynamic binding action.
387 ;;; Blocks are annotated with the current cleanup so that dynamic
388 ;;; bindings can be removed when control is transferred out of the
389 ;;; binding environment. We arrange for changes in dynamic bindings to
390 ;;; happen at block boundaries, so that cleanup code may easily be
391 ;;; inserted. The "mess-up" action is explicitly represented by a
392 ;;; funny function call or Entry node.
394 ;;; We guarantee that cleanups only need to be done at block boundaries
395 ;;; by requiring that the exit continuations initially head their
396 ;;; blocks, and then by not merging blocks when there is a cleanup
399 ;; The kind of thing that has to be cleaned up.
400 (kind (required-argument)
401 :type (member :special-bind :catch :unwind-protect :block :tagbody))
402 ;; The node that messes things up. This is the last node in the
403 ;; non-messed-up environment. Null only temporarily. This could be
404 ;; deleted due to unreachability.
405 (mess-up nil :type (or node null))
406 ;; A list of all the NLX-Info structures whose NLX-Info-Cleanup is
407 ;; this cleanup. This is filled in by environment analysis.
408 (nlx-info nil :type list))
409 (defprinter (cleanup)
412 (nlx-info :test nlx-info))
414 ;;; The ENVIRONMENT structure represents the result of environment analysis.
415 (defstruct environment
416 ;; the function that allocates this environment
417 (function (required-argument) :type clambda)
418 ;; a list of all the lambdas that allocate variables in this environment
419 (lambdas nil :type list)
420 ;; a list of all the lambda-vars and NLX-Infos needed from enclosing
421 ;; environments by code in this environment
422 (closure nil :type list)
423 ;; a list of NLX-Info structures describing all the non-local exits
424 ;; into this environment
425 (nlx-info nil :type list)
426 ;; some kind of info used by the back end
428 (defprinter (environment)
430 (closure :test closure)
431 (nlx-info :test nlx-info))
433 ;;; The TAIL-SET structure is used to accumulate information about
434 ;;; tail-recursive local calls. The "tail set" is effectively the
435 ;;; transitive closure of the "is called tail-recursively by"
438 ;;; All functions in the same tail set share the same TAIL-SET
439 ;;; structure. Initially each function has its own TAIL-SET, but when
440 ;;; IR1-OPTIMIZE-RETURN notices a tail local call, it joins the tail
441 ;;; sets of the called function and the calling function.
443 ;;; The tail set is somewhat approximate, because it is too early to
444 ;;; be sure which calls will be TR. Any call that *might* end up TR
445 ;;; causes tail-set merging.
447 ;; a list of all the lambdas in this tail set
448 (functions nil :type list)
449 ;; our current best guess of the type returned by these functions.
450 ;; This is the union across all the functions of the return node's
451 ;; RESULT-TYPE. excluding local calls.
452 (type *wild-type* :type ctype)
453 ;; some info used by the back end
455 (defprinter (tail-set)
460 ;;; The NLX-Info structure is used to collect various information
461 ;;; about non-local exits. This is effectively an annotation on the
462 ;;; CONTINUATION, although it is accessed by searching in the
463 ;;; ENVIRONMENT-NLX-INFO.
464 (def!struct (nlx-info (:make-load-form-fun ignore-it))
465 ;; the cleanup associated with this exit. In a catch or
466 ;; unwind-protect, this is the :CATCH or :UNWIND-PROTECT cleanup,
467 ;; and not the cleanup for the escape block. The CLEANUP-KIND of
468 ;; this thus provides a good indication of what kind of exit is
470 (cleanup (required-argument) :type cleanup)
471 ;; the continuation exited to (the CONT of the EXIT nodes). If this
472 ;; exit is from an escape function (CATCH or UNWIND-PROTECT), then
473 ;; environment analysis deletes the escape function and instead has
474 ;; the %NLX-ENTRY use this continuation.
476 ;; This slot is primarily an indication of where this exit delivers
477 ;; its values to (if any), but it is also used as a sort of name to
478 ;; allow us to find the NLX-Info that corresponds to a given exit.
479 ;; For this purpose, the Entry must also be used to disambiguate,
480 ;; since exits to different places may deliver their result to the
481 ;; same continuation.
482 (continuation (required-argument) :type continuation)
483 ;; the entry stub inserted by environment analysis. This is a block
484 ;; containing a call to the %NLX-Entry funny function that has the
485 ;; original exit destination as its successor. Null only
487 (target nil :type (or cblock null))
488 ;; some kind of info used by the back end
490 (defprinter (nlx-info)
497 ;;; Variables, constants and functions are all represented by LEAF
498 ;;; structures. A reference to a LEAF is indicated by a REF node. This
499 ;;; allows us to easily substitute one for the other without actually
500 ;;; hacking the flow graph.
501 (def!struct (leaf (:make-load-form-fun ignore-it)
503 ;; some name for this leaf. The exact significance of the name
504 ;; depends on what kind of leaf it is. In a LAMBDA-VAR or
505 ;; GLOBAL-VAR, this is the symbol name of the variable. In a
506 ;; functional that is from a DEFUN, this is the defined name. In
507 ;; other functionals, this is a descriptive string.
509 ;; the type which values of this leaf must have
510 (type *universal-type* :type ctype)
511 ;; where the TYPE information came from:
512 ;; :DECLARED, from a declaration.
513 ;; :ASSUMED, from uses of the object.
514 ;; :DEFINED, from examination of the definition.
515 ;; FIXME: This should be a named type. (LEAF-WHERE-FROM?)
516 (where-from :assumed :type (member :declared :assumed :defined))
517 ;; list of the REF nodes for this leaf
519 ;; true if there was ever a REF or SET node for this leaf. This may
520 ;; be true when REFS and SETS are null, since code can be deleted.
521 (ever-used nil :type boolean)
522 ;; some kind of info used by the back end
525 ;;; The CONSTANT structure is used to represent known constant values.
526 ;;; If NAME is not null, then it is the name of the named constant
527 ;;; which this leaf corresponds to, otherwise this is an anonymous
529 (def!struct (constant (:include leaf))
530 ;; the value of the constant
532 (defprinter (constant)
536 ;;; The BASIC-VAR structure represents information common to all
537 ;;; variables which don't correspond to known local functions.
538 (def!struct (basic-var (:include leaf) (:constructor nil))
539 ;; Lists of the set nodes for this variable.
540 (sets () :type list))
542 ;;; The GLOBAL-VAR structure represents a value hung off of the symbol
543 ;;; NAME. We use a :CONSTANT VAR when we know that the thing is a
544 ;;; constant, but don't know what the value is at compile time.
545 (def!struct (global-var (:include basic-var))
546 ;; kind of variable described
547 (kind (required-argument)
548 :type (member :special :global-function :constant :global)))
549 (defprinter (global-var)
551 (type :test (not (eq type *universal-type*)))
552 (where-from :test (not (eq where-from :assumed)))
555 ;;; The SLOT-ACCESSOR structure represents slot accessor functions. It
556 ;;; is a subtype of GLOBAL-VAR to make it look more like a normal
558 (def!struct (slot-accessor (:include global-var
559 (where-from :defined)
560 (kind :global-function)))
561 ;; The description of the structure that this is an accessor for.
562 (for (required-argument) :type sb!xc:class)
563 ;; The slot description of the slot.
564 (slot (required-argument)))
565 (defprinter (slot-accessor)
570 ;;; The DEFINED-FUNCTION structure represents functions that are
571 ;;; defined in the same compilation block, or that have inline
572 ;;; expansions, or have a non-NIL INLINEP value. Whenever we change
573 ;;; the INLINEP state (i.e. an inline proclamation) we copy the
574 ;;; structure so that former inlinep values are preserved.
575 (def!struct (defined-function (:include global-var
576 (where-from :defined)
577 (kind :global-function)))
578 ;; The values of INLINEP and INLINE-EXPANSION initialized from the
579 ;; global environment.
580 (inlinep nil :type inlinep)
581 (inline-expansion nil :type (or cons null))
582 ;; The block-local definition of this function (either because it
583 ;; was semi-inline, or because it was defined in this block.) If
584 ;; this function is not an entry point, then this may be deleted or
585 ;; let-converted. Null if we haven't converted the expansion yet.
586 (functional nil :type (or functional null)))
587 (defprinter (defined-function)
590 (functional :test functional))
594 ;;; We default the WHERE-FROM and TYPE slots to :DEFINED and FUNCTION.
595 ;;; We don't normally manipulate function types for defined functions,
596 ;;; but if someone wants to know, an approximation is there.
597 (def!struct (functional (:include leaf
598 (where-from :defined)
599 (type (specifier-type 'function))))
600 ;; Some information about how this function is used. These values are
604 ;; an ordinary function, callable using local call
607 ;; a lambda that is used in only one local call, and has in
608 ;; effect been substituted directly inline. The return node is
609 ;; deleted, and the result is computed with the actual result
610 ;; continuation for the call.
613 ;; Similar to :LET, but the call is an MV-CALL.
616 ;; similar to a LET, but can have other than one call as long as
617 ;; there is at most one non-tail call.
620 ;; a lambda that is an entry-point for an optional-dispatch.
621 ;; Similar to NIL, but requires greater caution, since local call
622 ;; analysis may create new references to this function. Also, the
623 ;; function cannot be deleted even if it has *no* references. The
624 ;; Optional-Dispatch is in the LAMDBA-OPTIONAL-DISPATCH.
627 ;; an external entry point lambda. The function it is an entry
628 ;; for is in the Entry-Function.
631 ;; a top-level lambda, holding a compiled top-level form.
632 ;; Compiled very much like NIL, but provides an indication of
633 ;; top-level context. A top-level lambda should have *no*
634 ;; references. Its Entry-Function is a self-pointer.
637 ;; After a component is compiled, we clobber any top-level code
638 ;; references to its non-closure XEPs with dummy FUNCTIONAL
639 ;; structures having this kind. This prevents the retained
640 ;; top-level code from holding onto the IR for the code it
645 ;; special functions used internally by CATCH and UNWIND-PROTECT.
646 ;; These are pretty much like a normal function (NIL), but are
647 ;; treated specially by local call analysis and stuff. Neither
648 ;; kind should ever be given an XEP even though they appear as
649 ;; args to funny functions. An :ESCAPE function is never actually
650 ;; called, and thus doesn't need to have code generated for it.
653 ;; This function has been found to be uncallable, and has been
654 ;; marked for deletion.
655 (kind nil :type (member nil :optional :deleted :external :top-level :escape
656 :cleanup :let :mv-let :assignment
658 ;; In a normal function, this is the external entry point (XEP)
659 ;; lambda for this function, if any. Each function that is used
660 ;; other than in a local call has an XEP, and all of the
661 ;; non-local-call references are replaced with references to the
664 ;; In an XEP lambda (indicated by the :External kind), this is the
665 ;; function that the XEP is an entry-point for. The body contains
666 ;; local calls to all the actual entry points in the function. In a
667 ;; :Top-Level lambda (which is its own XEP) this is a self-pointer.
669 ;; With all other kinds, this is null.
670 (entry-function nil :type (or functional null))
671 ;; the value of any inline/notinline declaration for a local function
672 (inlinep nil :type inlinep)
673 ;; If we have a lambda that can be used as in inline expansion for
674 ;; this function, then this is it. If there is no source-level
675 ;; lambda corresponding to this function then this is Null (but then
676 ;; INLINEP will always be NIL as well.)
677 (inline-expansion nil :type list)
678 ;; the lexical environment that the inline-expansion should be converted in
679 (lexenv *lexenv* :type lexenv)
680 ;; the original function or macro lambda list, or :UNSPECIFIED if
681 ;; this is a compiler created function
682 (arg-documentation nil :type (or list (member :unspecified)))
683 ;; various rare miscellaneous info that drives code generation & stuff
684 (plist () :type list))
685 (defprinter (functional)
688 ;;; The CLAMBDA only deals with required lexical arguments. Special,
689 ;;; optional, keyword and rest arguments are handled by transforming
690 ;;; into simpler stuff.
691 (def!struct (clambda (:include functional)
693 (:predicate lambda-p)
694 (:constructor make-lambda)
695 (:copier copy-lambda))
696 ;; List of lambda-var descriptors for args.
697 (vars nil :type list)
698 ;; If this function was ever a :OPTIONAL function (an entry-point
699 ;; for an optional-dispatch), then this is that optional-dispatch.
700 ;; The optional dispatch will be :DELETED if this function is no
702 (optional-dispatch nil :type (or optional-dispatch null))
703 ;; The Bind node for this Lambda. This node marks the beginning of
704 ;; the lambda, and serves to explicitly represent the lambda binding
705 ;; semantics within the flow graph representation. Null in deleted
706 ;; functions, and also in LETs where we deleted the call & bind
707 ;; (because there are no variables left), but have not yet actually
708 ;; deleted the lambda yet.
709 (bind nil :type (or bind null))
710 ;; The Return node for this Lambda, or NIL if it has been deleted.
711 ;; This marks the end of the lambda, receiving the result of the
712 ;; body. In a let, the return node is deleted, and the body delivers
713 ;; the value to the actual continuation. The return may also be
714 ;; deleted if it is unreachable.
715 (return nil :type (or creturn null))
716 ;; If this is a let, then the Lambda whose Lets list we are in,
717 ;; otherwise this is a self-pointer.
718 (home nil :type (or clambda null))
719 ;; A list of all the all the lambdas that have been let-substituted
720 ;; in this lambda. This is only non-null in lambdas that aren't
723 ;; A list of all the Entry nodes in this function and its lets. Null
725 (entries () :type list)
726 ;; A list of all the functions directly called from this function
727 ;; (or one of its lets) using a non-let local call. May include
728 ;; deleted functions because nobody bothers to clear them out.
729 (calls () :type list)
730 ;; The Tail-Set that this lambda is in. Null during creation and in
732 (tail-set nil :type (or tail-set null))
733 ;; The structure which represents the environment that this
734 ;; Function's variables are allocated in. This is filled in by
735 ;; environment analysis. In a let, this is EQ to our home's
737 (environment nil :type (or environment null))
738 ;; In a LET, this is the NODE-LEXENV of the combination node. We
739 ;; retain it so that if the let is deleted (due to a lack of vars),
740 ;; we will still have caller's lexenv to figure out which cleanup is
742 (call-lexenv nil :type (or lexenv null)))
743 (defprinter (clambda :conc-name lambda-)
745 (type :test (not (eq type *universal-type*)))
746 (where-from :test (not (eq where-from :assumed)))
747 (vars :prin1 (mapcar #'leaf-name vars)))
749 ;;; The OPTIONAL-DISPATCH leaf is used to represent hairy lambdas. It
750 ;;; is a FUNCTIONAL, like LAMBDA. Each legal number of arguments has a
751 ;;; function which is called when that number of arguments is passed.
752 ;;; The function is called with all the arguments actually passed. If
753 ;;; additional arguments are legal, then the LEXPR style MORE-ENTRY
754 ;;; handles them. The value returned by the function is the value
755 ;;; which results from calling the OPTIONAL-DISPATCH.
757 ;;; The theory is that each entry-point function calls the next entry
758 ;;; point tail-recursively, passing all the arguments passed in and
759 ;;; the default for the argument the entry point is for. The last
760 ;;; entry point calls the real body of the function. In the presence
761 ;;; of supplied-p args and other hair, things are more complicated. In
762 ;;; general, there is a distinct internal function that takes the
763 ;;; supplied-p args as parameters. The preceding entry point calls
764 ;;; this function with NIL filled in for the supplied-p args, while
765 ;;; the current entry point calls it with T in the supplied-p
768 ;;; Note that it is easy to turn a call with a known number of
769 ;;; arguments into a direct call to the appropriate entry-point
770 ;;; function, so functions that are compiled together can avoid doing
772 (def!struct (optional-dispatch (:include functional))
773 ;; the original parsed argument list, for anyone who cares
774 (arglist nil :type list)
775 ;; true if &ALLOW-OTHER-KEYS was supplied
776 (allowp nil :type boolean)
777 ;; true if &KEY was specified (doesn't necessarily mean that there
778 ;; are any keyword arguments...)
779 (keyp nil :type boolean)
780 ;; the number of required arguments. This is the smallest legal
781 ;; number of arguments.
782 (min-args 0 :type unsigned-byte)
783 ;; the total number of required and optional arguments. Args at
784 ;; positions >= to this are &REST, &KEY or illegal args.
785 (max-args 0 :type unsigned-byte)
786 ;; list of the LAMBDAs which are the entry points for non-rest,
787 ;; non-key calls. The entry for MIN-ARGS is first, MIN-ARGS+1
788 ;; second, ... MAX-ARGS last. The last entry-point always calls the
789 ;; main entry; in simple cases it may be the main entry.
790 (entry-points nil :type list)
791 ;; An entry point which takes MAX-ARGS fixed arguments followed by
792 ;; an argument context pointer and an argument count. This entry
793 ;; point deals with listifying rest args and parsing keywords. This
794 ;; is null when extra arguments aren't legal.
795 (more-entry nil :type (or clambda null))
796 ;; The main entry-point into the function, which takes all arguments
797 ;; including keywords as fixed arguments. The format of the
798 ;; arguments must be determined by examining the arglist. This may
799 ;; be used by callers that supply at least Max-Args arguments and
800 ;; know what they are doing.
801 (main-entry nil :type (or clambda null)))
802 (defprinter (optional-dispatch)
804 (type :test (not (eq type *universal-type*)))
805 (where-from :test (not (eq where-from :assumed)))
811 (entry-points :test entry-points)
812 (more-entry :test more-entry)
815 ;;; The ARG-INFO structure allows us to tack various information onto
816 ;;; LAMBDA-VARs during IR1 conversion. If we use one of these things,
817 ;;; then the var will have to be massaged a bit before it is simple
820 ;; true if this arg is to be specially bound
821 (specialp nil :type boolean)
822 ;; the kind of argument being described. Required args only have arg
823 ;; info structures if they are special.
824 (kind (required-argument) :type (member :required :optional :keyword :rest
825 :more-context :more-count))
826 ;; If true, this is the VAR for SUPPLIED-P variable of a keyword or
827 ;; optional arg. This is true for keywords with non-constant
828 ;; defaults even when there is no user-specified supplied-p var.
829 (supplied-p nil :type (or lambda-var null))
830 ;; the default for a keyword or optional, represented as the
831 ;; original Lisp code. This is set to NIL in keyword arguments that
832 ;; are defaulted using the SUPPLIED-P arg.
833 (default nil :type t)
834 ;; the actual keyword for a keyword argument
835 (keyword nil :type (or keyword null)))
836 (defprinter (arg-info)
837 (specialp :test specialp)
839 (supplied-p :test supplied-p)
840 (default :test default)
841 (keyword :test keyword))
843 ;;; The LAMBDA-VAR structure represents a lexical lambda variable.
844 ;;; This structure is also used during IR1 conversion to describe
845 ;;; lambda arguments which may ultimately turn out not to be simple
848 ;;; LAMBDA-VARs with no REFs are considered to be deleted; environment
849 ;;; analysis isn't done on these variables, so the back end must check
850 ;;; for and ignore unreferenced variables. Note that a deleted
851 ;;; lambda-var may have sets; in this case the back end is still
852 ;;; responsible for propagating the Set-Value to the set's Cont.
853 (def!struct (lambda-var (:include basic-var))
854 ;; true if this variable has been declared IGNORE
855 (ignorep nil :type boolean)
856 ;; the CLAMBDA that this var belongs to. This may be null when we are
857 ;; building a lambda during IR1 conversion.
858 (home nil :type (or null clambda))
859 ;; This is set by environment analysis if it chooses an indirect
860 ;; (value cell) representation for this variable because it is both
861 ;; set and closed over.
862 (indirect nil :type boolean)
863 ;; The following two slots are only meaningful during IR1 conversion
864 ;; of hairy lambda vars:
866 ;; The ARG-INFO structure which holds information obtained from
868 (arg-info nil :type (or arg-info null))
869 ;; if true, the GLOBAL-VAR structure for the special variable which
870 ;; is to be bound to the value of this argument
871 (specvar nil :type (or global-var null))
872 ;; Set of the CONSTRAINTs on this variable. Used by constraint
873 ;; propagation. This is left null by the lambda pre-pass if it
874 ;; determine that this is a set closure variable, and is thus not a
875 ;; good subject for flow analysis.
876 (constraints nil :type (or sset null)))
877 (defprinter (lambda-var)
879 (type :test (not (eq type *universal-type*)))
880 (where-from :test (not (eq where-from :assumed)))
881 (ignorep :test ignorep)
882 (arg-info :test arg-info)
883 (specvar :test specvar))
885 ;;;; basic node types
887 ;;; A REF represents a reference to a LEAF. REF-REOPTIMIZE is
888 ;;; initially (and forever) NIL, since REFs don't receive any values
889 ;;; and don't have any IR1 optimizer.
890 (defstruct (ref (:include node (:reoptimize nil))
891 (:constructor make-ref (derived-type leaf)))
892 ;; The leaf referenced.
893 (leaf nil :type leaf))
897 ;;; Naturally, the IF node always appears at the end of a block.
898 ;;; NODE-CONT is a dummy continuation, and is there only to keep
900 (defstruct (cif (:include node)
903 (:constructor make-if)
905 ;; CONTINUATION for the predicate
906 (test (required-argument) :type continuation)
907 ;; the blocks that we execute next in true and false case,
908 ;; respectively (may be the same)
909 (consequent (required-argument) :type cblock)
910 (alternative (required-argument) :type cblock))
911 (defprinter (cif :conc-name if-)
912 (test :prin1 (continuation-use test))
916 (defstruct (cset (:include node
917 (derived-type *universal-type*))
920 (:constructor make-set)
922 ;; descriptor for the variable set
923 (var (required-argument) :type basic-var)
924 ;; continuation for the value form
925 (value (required-argument) :type continuation))
926 (defprinter (cset :conc-name set-)
928 (value :prin1 (continuation-use value)))
930 ;;; The BASIC-COMBINATION structure is used to represent both normal
931 ;;; and multiple value combinations. In a local function call, this
932 ;;; node appears at the end of its block and the body of the called
933 ;;; function appears as the successor. The NODE-CONT remains the
934 ;;; continuation which receives the value of the call.
935 (defstruct (basic-combination (:include node)
937 ;; continuation for the function
938 (fun (required-argument) :type continuation)
939 ;; list of CONTINUATIONs for the args. In a local call, an argument
940 ;; continuation may be replaced with NIL to indicate that the
941 ;; corresponding variable is unreferenced, and thus no argument
942 ;; value need be passed.
943 (args nil :type list)
944 ;; the kind of function call being made. :LOCAL means that this is a
945 ;; local call to a function in the same component, and that argument
946 ;; syntax checking has been done, etc. Calls to known global
947 ;; functions are represented by storing the FUNCTION-INFO for the
948 ;; function in this slot. :FULL is a call to an (as yet) unknown
949 ;; function. :ERROR is like :FULL, but means that we have discovered
950 ;; that the call contains an error, and should not be reconsidered
952 (kind :full :type (or (member :local :full :error) function-info))
953 ;; some kind of information attached to this node by the back end
956 ;;; The COMBINATION node represents all normal function calls,
957 ;;; including FUNCALL. This is distinct from BASIC-COMBINATION so that
958 ;;; an MV-COMBINATION isn't COMBINATION-P.
959 (defstruct (combination (:include basic-combination)
960 (:constructor make-combination (fun))))
961 (defprinter (combination)
962 (fun :prin1 (continuation-use fun))
963 (args :prin1 (mapcar (lambda (x)
969 ;;; An MV-COMBINATION is to MULTIPLE-VALUE-CALL as a COMBINATION is to
970 ;;; FUNCALL. This is used to implement all the multiple-value
972 (defstruct (mv-combination (:include basic-combination)
973 (:constructor make-mv-combination (fun))))
974 (defprinter (mv-combination)
975 (fun :prin1 (continuation-use fun))
976 (args :prin1 (mapcar #'continuation-use args)))
978 ;;; The Bind node marks the beginning of a lambda body and represents
979 ;;; the creation and initialization of the variables.
980 (defstruct (bind (:include node))
981 ;; the lambda we are binding variables for. Null when we are
982 ;; creating the LAMBDA during IR1 translation.
983 (lambda nil :type (or clambda null)))
987 ;;; The Return node marks the end of a lambda body. It collects the
988 ;;; return values and represents the control transfer on return. This
989 ;;; is also where we stick information used for Tail-Set type
991 (defstruct (creturn (:include node)
993 (:predicate return-p)
994 (:constructor make-return)
995 (:copier copy-return))
996 ;; the lambda we are returning from. Null temporarily during
998 (lambda nil :type (or clambda null))
999 ;; the continuation which yields the value of the lambda
1000 (result (required-argument) :type continuation)
1001 ;; the union of the node-derived-type of all uses of the result
1002 ;; other than by a local call, intersected with the result's
1003 ;; asserted-type. If there are no non-call uses, this is
1005 (result-type *wild-type* :type ctype))
1006 (defprinter (creturn :conc-name return-)
1010 ;;;; non-local exit support
1012 ;;;; In IR1, we insert special nodes to mark potentially non-local
1015 ;;; The ENTRY node serves to mark the start of the dynamic extent of a
1016 ;;; lexical exit. It is the mess-up node for the corresponding :Entry
1018 (defstruct (entry (:include node))
1019 ;; All of the Exit nodes for potential non-local exits to this point.
1020 (exits nil :type list)
1021 ;; The cleanup for this entry. NULL only temporarily.
1022 (cleanup nil :type (or cleanup null)))
1023 (defprinter (entry))
1025 ;;; The EXIT node marks the place at which exit code would be emitted,
1026 ;;; if necessary. This is interposed between the uses of the exit
1027 ;;; continuation and the exit continuation's DEST. Instead of using
1028 ;;; the returned value being delivered directly to the exit
1029 ;;; continuation, it is delivered to our VALUE continuation. The
1030 ;;; original exit continuation is the exit node's CONT.
1031 (defstruct (exit (:include node))
1032 ;; The Entry node that this is an exit for. If null, this is a
1033 ;; degenerate exit. A degenerate exit is used to "fill" an empty
1034 ;; block (which isn't allowed in IR1.) In a degenerate exit, Value
1035 ;; is always also null.
1036 (entry nil :type (or entry null))
1037 ;; The continuation yeilding the value we are to exit with. If NIL,
1038 ;; then no value is desired (as in GO).
1039 (value nil :type (or continuation null)))
1042 (value :test value))
1044 ;;;; miscellaneous IR1 structures
1046 (defstruct (undefined-warning
1047 #-no-ansi-print-object
1048 (:print-object (lambda (x s)
1049 (print-unreadable-object (x s :type t)
1050 (prin1 (undefined-warning-name x) s)))))
1051 ;; The name of the unknown thing.
1052 (name nil :type (or symbol list))
1053 ;; The kind of reference to Name.
1054 (kind (required-argument) :type (member :function :type :variable))
1055 ;; The number of times this thing was used.
1056 (count 0 :type unsigned-byte)
1057 ;; A list of COMPILER-ERROR-CONTEXT structures describing places
1058 ;; where this thing was used. Note that we only record the first
1059 ;; *UNDEFINED-WARNING-LIMIT* calls.
1060 (warnings () :type list))
1062 ;;;; Freeze some structure types to speed type testing.
1065 (declaim (freeze-type node leaf lexenv continuation cblock component cleanup
1066 environment tail-set nlx-info))